Seeley is also the author of the comic Hack/Slash series, and will participate in the production of the Hack/Slash feature film. It was due to be released by Universal Pictures in 2009. Hack/Slash is now available digitally through Devil's Due Digital.

His Image Comics series, Loaded Bible, gained a great deal of attention for its political theme of Jesus vs. Vampires in a post-apocalyptic Christian-run society. Loaded Bible is also available through Devil's Due Digital.

Seeley pencilled New Exiles, and Weapon X: First Class. and he both wrote and illustrated the mini-series Ant-Man & Wasp.

Seeley's webcomic Colt Noble and the Megalords debuted on Nerd City Online on August 3, 2009. He writes currently on the Werewolf comic Wild Game, which based on the Underworld and An American Werewolf in London.